I loved the Civil War event. It was a great way to connect whats going on in the movies and comics to the game. I also loved the packs and new costumes, etc.
But for me the X-Men have always been my go to comic. I don't really even like the Avengers much. With the new X-Men movie coming out, I can help but thing an Apocalypse related event would be awesome. I can't help but think back to X-men Legends and want more of that.